Add test for current CTAD support with RangePolicy (kokkos#6803)

* Add test for current CTAD support with RangePolicy

Co-authored-by: Nevin Liber <nliber@anl.gov>

* Rework CTAD test to avoid "memeber <bla> was declared but never referenced" warnings with icpc 19

* Attempt to fix CI

* Attempt to eliminate maybe unused warning in icpc

* Disable CTAD tests for nvcc < 11.2
as compiler bugs prevent CTAD expressions inside decltype

---------

Co-authored-by: Nevin Liber <nliber@anl.gov>
Co-authored-by: Nevin ":-)" Liber <nliber+github@gmail.com>

core/unit_test/CMakeLists.txt

@@ -86,6 +86,7 @@ SET(COMPILE_ONLY_SOURCES
   TestDetectionIdiom.cpp
   TestBitManipulation.cpp
   TestInterOp.cpp
+  TestRangePolicyCTAD.cpp
   TestStringManipulation.cpp
   TestVersionMacros.cpp
   TestViewRank.cpp

core/unit_test/TestRangePolicyCTAD.cpp

@@ -0,0 +1,87 @@
+//@HEADER
+// ************************************************************************
+//
+//                        Kokkos v. 4.0
+//       Copyright (2022) National Technology & Engineering
+//               Solutions of Sandia, LLC (NTESS).
+//
+// Under the terms of Contract DE-NA0003525 with NTESS,
+// the U.S. Government retains certain rights in this software.
+//
+// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
+// See https://kokkos.org/LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//@HEADER
+
+#include <Kokkos_Core.hpp>
+#include "Kokkos_Core_fwd.hpp"
+
+namespace {
+
+template <class... Args>
+using PolicyMaker = decltype(::Kokkos::RangePolicy(std::declval<Args>()...));
+
+template <class Policy, class... Args>
+inline constexpr bool IsSamePolicy =
+    std::is_same_v<Policy, PolicyMaker<Args...>>;
+
+#define KOKKOS_TEST_RANGE_POLICY(...) static_assert(IsSamePolicy<__VA_ARGS__>)
+
+struct TestRangePolicyCTAD {
+  struct ImplicitlyConvertibleToDefaultExecutionSpace {
+    operator Kokkos::DefaultExecutionSpace() const {
+      return Kokkos::DefaultExecutionSpace();
+    }
+  };
+  static_assert(!Kokkos::is_execution_space_v<
+                ImplicitlyConvertibleToDefaultExecutionSpace>);
+
+  using des = Kokkos::DefaultExecutionSpace;
+  using nes = ImplicitlyConvertibleToDefaultExecutionSpace;
+  using i64 = int64_t;
+  using i32 = int32_t;
+  using cs  = Kokkos::ChunkSize;
+
+  // RangePolicy()
+
+  // Guard against GGC 8.4 bug
+  // error: cannot deduce template arguments for ‘RangePolicy’ from ()
+  // error: template argument 2 is invalid
+#if !defined(KOKKOS_COMPILER_GNU) || (KOKKOS_COMPILER_GNU > 900)
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<> /*, no argument */);
+#endif
+
+  // RangePolicy(index_type, index_type)
+
+#if !defined(KOKKOS_COMPILER_NVCC) || KOKKOS_COMPILER_NVCC >= 1120
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i64, i64);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i64, i32);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i32, i64);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i32, i32);
+
+  // RangePolicy(index_type, index_type, Args...)
+
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i64, i64, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i64, i32, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i32, i64, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, i32, i32, cs);
+
+  // RangePolicy(execution_space, index_type, index_type)
+
+  // none (ambiguous deduction for template arguments)
+
+  // RangePolicy(execution_space, index_type, index_type, Args...)
+
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, des, i64, i64, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, des, i32, i32, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, nes, i64, i64, cs);
+  KOKKOS_TEST_RANGE_POLICY(Kokkos::RangePolicy<>, nes, i32, i32, cs);
+#endif
+};  // TestRangePolicyCTAD struct
+
+// To eliminate maybe_unused warning on some compilers
+const Kokkos::DefaultExecutionSpace des =
+    TestRangePolicyCTAD::ImplicitlyConvertibleToDefaultExecutionSpace();
+
+}  // namespace